> Actually (though not that it matters really) the idea I was
> speculating about, with the hypothetically smarter linker and
> packaging, was something similar to garbage collection for libraries
> -- whether you might be able to design a hypothetical system that
> keeps older copies of particular versions of libs around
> automatically, at least until they're no longer needed by any other
> binary on the system (of course you'd have to be able to decide
> somewhat what "no longer needed" meant).
> The former copy wouldn't be elegible for removal from the system until
> no package still contained an executable or library that needed it to
> form a "consistent set".
You may want to look at what "deborphan" package does.
Debian as packaging system provides such infrastructure,
removing library packages which are no longer required by
any other.
However, we also support locally installed library packages,
outside of Debian control, and that complicates things a bit.
regards,
junichi